A technology is known in which the features of the shape of a single stroke of a character or a drawing, which is written by hand by a user, are represented by the curvature of the shape.
In the abovementioned conventional technology, at each point constituting a point sequence, an expectation value of the curvature of the shape identified by the point sequence is calculated with the point as the reference; and feature quantities that represent the dimensionality of the points constituting the point sequence are extracted so as to represent the features of the shape identified by the point sequence. For that reason, in the abovementioned conventional technology, the dimensionality of the feature quantities is high and the volume of data increases.
Moreover, in the abovementioned conventional technology, the features of a point sequence group, which is a set of point sequences, cannot be represented directly. Thus, in order to represent the features of the entire point sequence group, the features of each point sequence constituting the point sequence group are extracted. As a result, the volume of data goes on increasing.